Powered Rear Window for 2nd Gens

I really hope this has not been posted already, however, I am trying to figure out a way to install a power DOWNWARD sliding rear glass. Think of the way 4-Runners and Tundra's rear glass slide down. This is going to apparently be a completely custom ob. Any thoughts?

 

This is on my wish list as well. Another example to check out is the Ford Explorer Sport Trac's rear window.

I was in traffic stuck at a light on my way home, after having a new, full ARB suspension put on my truck, and sitting behind and in the lane next to a Ford Sport Trac when the driver rolled the back window down a bit.

I immediately forgot about my new suspension and started jonesing on that powered roll down back window. Nice job, Ford!!! WTF, Toyota?!?

I'd really like to have that option on my truck. Fortunately, Tacomas are made for customizing I've seen enough episodes of Overhaulin' to know there's gotta be a way to make it happen.